Transmission substitution system



June 13, 1939. J. c. WALTER 2,161,884

TRANSMISSION SUBSTITUTIO SYSTEM Filed OcAt. 3, 1936 3 Sheets-Sheet l WN NN L IN VEN TOR.

. June 13, 1939.

J. C. WALTER TRANSMISSION' SUBSTITUTION SYSTEM Filed Oct. I5, 1936 3 Sheets-Sheet 2 BY nl ATTORNEY June 13, 1939. J, c, WALTER 2,161,884

TRANSMISSION SUBSTITUTION SYSTEM Filed Oct. 34, 1936 3 Sheets-Sheet I5 EF Q POSITION No.

CUNTACTOR 1 E 3 4 .98 Y W l INVENToR.

ATTORNEY.

Patented Jun'e13, 1939 2,161,884 TRANSMISSION snns'rrru'non John C.

Walter, Collingswood, N. J.. assignor to Wired Badin, Inc., New York, N. Y., a corporation of Delaware Application octoberw 3, 193s, No. 103,922

` 7 claims. [(cl. 11s-15) My invention pertains in general to signal transmission systems and specifically relates to a multiple transmitter organization.

I'he principal object of the invention consists in providing a transmitting organization providing means for automatically rendering a spare transmitter eiiectivedn the 'event of an overload in the transmitting organization.

A further object of the` invention comprises providing a group of signal transmitters and an auxiliary stand-by Signal transmitter common to said group of transmitters with means for automatically associating said stand-by transmitter with the circuits of any one of the transmitters of said group to replace the function of that transmitter in the group.

A further object of the invention comprises providing a wired radio distribution system having means for simultaneously transmitting a plurality of programs over a common transmission medium with Stand-by transmission means rendered automatically eiIective in an emergency.

A further object of the invention resides in the disposition and details of automatic circuits and protective circuits incorporated in the system.

In the drawings which accompany and form a part of the specication, and in which like reference numerals designate corresponding parts:

Fig. 1 is a schematic representation of an electrical transmission organization in accordance with one embodiment of the invention;

Fig. 2 is a diagrammatic representation of a control circuit lemployed in the system of Fig. l;

111g. 3 is a schematic representation of protectivecircuit of the system of Fig. 1; and

Fig. 4 is a graphical representation showing the relative operative positions of a switch system employed in the organimtion of Fig. 2.

General transmission organization `39 lxiiocycles, and 52 kilocycles, respectively.

These carrier frequency ranges correspond to individuai program channels, designated as channels A, Band C, each comprising a separate program modulation, and all transmitted Simultaneously.

An input circuit to the illter 2 is connected with two movable contactors 1 and 3,. The input circuit to filter 3 is connected with movable contactors Sand III, andthe input circuit to filter 4 is connected withvmovable contactors ii and I2. These movable contactors, when in a right hand position, as shown in Fig. l, complete circuits from high power am'pliiiers I3, i4 and Ii to the filters 2, 3 and 4,' respectively. The movable contactors for each program channel are ,adapted to be moved to a left hand position by transfer solenoids i6, i1 and I8, respectively.

'I'he high power amplifiers I3, I4 and l5 are controlled by the output from low power ampliilers i9, 20and 2|, respectively. Movable contactors 22 and 23 are connected with the output circuit of an A channel program 'source 24, and, when in a right hand position as shown in Fig. 1, complete a connection Afrom the source 24 to the low power ampiiiier I9. Movable contactors 25 and 26 are connected with the output of a B channel program source 21 and, when in a right hand position as shown in Fig. l, complete a circuit from the source 2'1 to the low power ampliiler 2D. Similarly, movable contactors 28 and 23 are connected with the output of a C channel program source 30 and, when in a right hand position as shown in Fig. 1, complete a circuit with the input of low power amplifier 2l.

Thev program sources 24, 21 and 30 are indicative of separate studios including suitable ampli.-

cation and modulation equipment for producing the necessary modulated program frequencies to be ampliiied over the low power and high power ampliilers. Rectier units 43, 4I and 42 are individually associated with the ampliiiers of the three program channels, and control units 43, 44 and 45 are also individually associated with the equipment of each channel. 'I'he rectifier units comprise means for supplying the necessary operating voltages to the amplifiers, and the control units include meters and relays associated in the controlling operations for each channel.

Auxiliary transmission equipment An auxiliary transmitter unit` is provided and includes a high power amplier 41, low power amplifier 4I, a rectier unit 49, and a control unit 51|. These units correspond to the similar units of the -channels A, B, and C. All of the transmitters are of the untuned anode circuit type. l

In one aspect of the invention, the amplifiers n and u may be provided with circuit systems respectively operative for amplifying the frequencies of the individual program channels. These different circuit systems are rendered individually effective by relays 52 and 53. Closing of relay 5| completes the circuit through selected parameters of the amplifiers to most eiciently amplify the frequencies within the range of lter 2. Closing of relay 52 controls the amplifiers to operate similarly with respect to frequencies of filter 3, and the closing of relay 53 will operate to effect the amplifiers to most eiciently amplify the frequencies within thev range of filter 3. The relays 5|, 52 and 53 are respectively energized by circuits extending through switch Contactors 54, 55 and 56. The Contactors 54, 55 and 56 are respectively controlled by solenoids I6, I1 and I8, so that the energization of any one of these solenoids will effect the corresponding one of the relays 5|, 52 or 53. This arrangement of frequency conditioning of the auxiliary equipment is for optional use.

Transfer circuit system The Contactors 22 and 23 may be moved into a left hand position by transfer solenoid 36. The Contactors 25 and 26 may be moved into a left hand position by tra vfer solenoid 31, and the Contactors 28 and 29 may be moved into a. left hand position by transfer solenoid 38. Contactors 3| and 32 are positioned to be moved away from their associated contactors upon energization of solenoid 36. Armatures 33 and 34 are positioned to be moved away from their associated contactors upon energization of solenoid 31, and contactor 35 is positioned to be moved away from its associated contactor upon energization of solenoid 38.

solenoids I6 and 36 are connected in parallel and include a connection through a switch Sila-99a to the rectier unit 48. The solenoids Il and 31 are connected in parallel and include a 'circuit through switch 68b-99b to rectier\ unit 4|; and the solenoids I8 andv38 are connected in parallel and include a circuit through switch 68c-99c to rectifier unit 42.

The other side of the circuit to solenoids I6 and 36 includes a connection to the normally closed contactor 33, this contactor being connected through contactors 3| and 35, as shown. The other side of the circuit to solenoids I1 and 31 includes a connection to contactor 3|, and the other side of the circuit to solenoids I8 and 38 includes a connection to contactor 34. Contactor 32' includes a connection to contacter 34. and the other side of contactor 32 is connected with contactor 35 and thence to a common circuit including the rectifier units 48, 4| and 42, as shown.

Typical control circuit ply transformer included in the rectifier unit.

Current transformers 12 and,13 are associated With the lines leading through contactors 14, 15, and 16 to the terminals 1|. The transformers 12 and 13 are included in circuits through instantaneous solenoids 8| and 82. The solenoids 8| and 82 which control Contactors .86 and 81 include an energizing circuit extending to a relay 18 and stepping magnet 19. Upon opening of the contactors 86 and' 81, the energizing circuit to solenoid 18 and magnet 19 is broken, whereuponthe relay 18 opens the energizing circuit to a solenoid 88.

Deenergization of solenoid 88 opens the contactors 14-16, whereupon the current'supply of the channel A transmitter is interrupted. 'The interruption of the energization circuit to magnet 19 permitsa spring to movethepawl armature 90 to engage a six-toothed ratchet 9| and advance the same one step. As soon as the contactors-14-16 are released to an open positioniby the deenergization of solenoid 88, the over-load condition is removed, whereupon energzation of instantaneous solenoids 8| and 82' is interrupted. Contactors 86 and 81 are then released to close the circuit to relay 18 and magnet 19.

The ratchet 9| is moved in a counter-clockwise direction by the pawl-armature 98 against a torsion spring. A dog-armature 92 is normally held in engagement with the teeth of ratchet 9| to prevent the ratchet from turning in a clockwise direction until the armature 92 is actuated by a release magnet 93. The shaft of ratchet 9| carries cams 94, 95, 96, which respectively operate Contactors 91, 98 and 99. One complete revolution of the ratchet 9| comprises a cycle of operations for the cams 94--96 and their respective contactors 91--99.

The cams 94-96 have peripheral configurations such as to produce the switching operations depicted in the table ofFig. 4. The shadedareas in the table of Fig. `4 indicate the duration of an upward contacting position of the contactors 91--99 for the six consecutive positions of the ratchet 9|, beginning with the first position just I described in connection with the interruption of the energizing circuit to magnet 19.

When the Contactors 14-16 are again closed, and if the over-load condition persists, the solenoids 8| and 82 are again energized, whereupon the Contactors 86 and 81 again interrupt the energizing circuit to solenoid 18 and magnet 19. Solenoid 18 again acts to release the Contactors 14-16, and the magnet 19 advances the ratchet 9| another step. If the over-load condition persists, the complete cycle of drop-out and "reset" operations results, as depicited in the table of Fig. 4. When the ratchet 9| is advanced to its sixth position the contactor 91 is raisedto an upward position and the Contactors 98 and 99 are lowered. -In this position the circuit to relay 18 and solenoid 88 becomes interrupted through contactor 99 and cannot be closed again until the ratchet 9| is reset to its normal starting position. In this sixth position of the ratchet 9|, the contacter 99 has been moved to engage contact 68, which controls the energizing circuits to the transfer relays for each channel.

When the ratchet sixth position, the 'contactor 91 completes an energizing circuit from the terminal |88 to magnet 93. The terminal |88 includes a circuit extending through a remote switch |8I, which may be manually or electrically operated to actuate the dog-armature 92 for releasing ratchet 9| so that the same may be returned to a normal position under action of its torsion spring. When the ratchet 9| is returned to its normal position the cams 94, 95 and 98 will likewise be returned to their initial or starting positions.

It will be noted from the table of Fig..4 that contactor 98 engageslts associated contact durvengages terminal 60a for channel A,

ing all of the intermediate positions o f thel ratchet 9| between the rst and last position. Thus, if the over-load condition on the lines of terminals rfll should be cleared while the ratchet 3| is in an intermediate position, an energizing circuit is completed through the contactor 33 to a heater element |3 of unit |32, which includes a bimetallic switch |04. The unit |32 constitutes a time delay switch, so adjusted that lf the ratchet 3| remains in an intermediate position for a predetermined period due to the clearing of the over-load fault, the switch |34 will close, due to the heating action of heater |03, 'whereupon an energizing circuit is established to the'r'elease magnet 93, thereby restoring ratchet 3| and its associated switching elements to an initial position.

When the over-load fault in a channel, such as channel A, has been removed, the normal transmitter can be restored to operation by manually or electrically closing the switch |3| associ- .ated with that channel. closed, the signal input and load output circuits are restored to the normal equipmentin the channel circuits, leaving the auxiliary transmitter free to accept service on demand from any other'channel that may become inoperative.

Transfer operation When, in the sixth position of the ratchet 9|. the contactor 99 engages the terminal 33, the transfer solenoids I6 and 39 of channel A will be energized. Energization of solenoid I3 causes the contactors 1 and 3 to be moved into a left hand position, and energization of solenoid 33 causes the contactors 22 and 23 to` be moved into a left hand position. When the contactors 1 and 8.are moved thus, the input. circuit to filter 2 for channel A is connected with the` output of the high power amplifier 41. Similarly, the out- -put of the program source 24 is directed to the input of the low power amplifier 43. As a result ofy this switching operation, the high power amplifier |3 and low power amplifier I3 become effectively isolated from the active program circuits of channel A. Similarly, the engagement of the switch 99 with the contact 33 in the equipment of any of the other channels will produce a similar result, provided that the auxiliary transmitter is not already in use as an active part of a program channel.

Protective lock-out circuit Referring to Fig. 3, when the contactor 39a the solenoid 36 will move the contactors 3| and 32 to a left hand position. This movement of contactor 3| opens the energizing circuit to solenoid 31 so that the same cannot be energized for a transfer operation. At the same time, the left hand position of contactor 32 opens a circuit which extends through-contactor 34 to solenoid 33 which pre-` vents energization of solenoid 33 while the contactor 32 is in a left hand position.

Similarly, assuming that contactor 99a has not engaged contact 60a, but that contactor 99h has engagedycontact 60h, the contactors 33 and 34 will then be moved to a left hand position upon energization of solenoid 31. 'Ihe contactor 33 will open the circuit to solenoid 36 to prevent energization of that solenoid, and the contactor 34 will open the energizing circuit extending from contactor 32 to the solenoid 33, thereby preventing energization of that solenoid.

Again, assuming that contactors 99a and 39h have not been closed, but that contactor 93e has When this switch is:

c la

been closed for channel C, the contactor 35 will then be moved to a left hand position which will interrupt the energizing circuit extending to the transfer solenoids 36 and 31. Accordingly, the energlzation of the transfer solenoids for any particular' channel in a transfer operation will lock out all other channels from further transfer operations, while the auxiliary transmitter is in use in the first channel.

Transfer control circuit function When an over-load fault occurs in a particular channel, the transfer control circuit for that channel, such as typically disclosed in Fig, 2, operates to open the power circuit for a short interval and then reclose the same. If the fault is then cleared, the transfer control circuit is automatically restored to a normal or initial position. In the event that the fault is not cleared upon reclosing of the power circuit, the power circuit is again opened and reclosed. This cycle of operation is continued until the fifth closing operation. Upon the sixth closing operation, if the fault has not then been cleared, the transfer relays are energized and the auxiliary transmitter transferred to the defective or inoperative channel in place of the normal equipment therein. In the event that the fault is cleared during any one of these testing operations of the transfer control circuit, up to its last testing operation, the transfer control circuit is' automatically returned to a normal or initial position. When the last testing operation is completed, the transfer operation takes place so that the auxiliary transmitter becomes effective in the required channel. When lthe proper fault has been cleared, the auxiliary transmitter is restored to a stand-by condition under control of the manual resetting switch connected with the controlling transfer control circuit.

Although a preferred form of automatic transfer circuit has lbeen disclosed, it will be recognized that various changes and equivalent organizations can be made without departing from the intended scope of the invention. Therefore, no limitation is intended other than as pointed out in the appended claims.

What I claim as new and original and desire to secure by Letters Patent of theUnited States is:

1. A signalling transmission system comprising, a plurality of transmission circuits corresponding to different signal channels and each having transmission equipment connected therein, auxiliary transmission equipment, and transfer control means having parts in each of said vcircuits responsive to a circuit fault for disconnecting the transmission equipment in said circuit, and operably substituting said auxiliary equipment therein in a selection operation among said transmission circuits as determined by said fault, said transfer control means including means responsive to control means of one of said transmission circuits for preventing the operation of any of the transfer control means in the other of said circuits from effectively operating at subsequent times to appropriate said auxiliary equipment vhile said auxiliary equipment is operably connected in one of said transmission circuits.

2. A transmission system comprising, a plurality of different signal transmission circuits each including a high frequency amplifier and a modulated high frequency source connected thereto, a spare high frequency amplifier, and switching an operation by the transfer fiers from its transmission circuit While automatically lsubstituting said spare amplifier therefor, said switching means comprising substitution control-circuit means, by-pass circuits extending from opposite sides of the normal amplifiers of said transmission circuits to connect the modulated high frequency source of a transmission circuit directly through said spare amplifier to by-pass the normal amplifier, and electromagnetic means responsive to currents transmitted over said control circuit means for selectively closing said by-pass circuits to connect said spare amplifier in a transmission circuit.

3. A transmission system comprising, a plurality of high frequency transmission systems with transmitter units having amplifiers tuned to different frequencies, a plurality of frequency se- 4. A transmission system comprising, a transmission network, a plurality of filter systems of different frequencyA characteristics connected with said network, a plurality of signal sources, a plurality of amplifier equipments, controlling transfer means for selectively rendering effective either of two of said equipments between any one, of said signal sources and one of said filter systems for transmitting signals through saidv filter system over said network, said controlling transfer means including circuits responsive to a fault means for disconnecting any one of said ampliin one of said equipments connected with a particular filter for substituting another equipment therefor in association with said filter.

5. A transmission system comprising, a plurality'of load circuits of different frequency characteristics, means for supplying currents in the event of transmission overload faults associated withsaid load circuits, a plurality of signal sources, a broadly tuned high frequency amplifier adapted to supply signals within a frequency range embracing all of said circuits, and switching means automatically operated in response to an overload y,current for selectively coupling said amplifier between selected ones of said signal sources and said load circuits.

6. A transmission system comprising, a plurality of transmission circuits including load circuits of different frequency characteristics, high frequency amplification equipment in each of said circuits, auxiliary high frequency amplification equipment, controlling means appurtenant to each of said transmission circuits and responsive to a fault for producing a predetermined sequence of fault-testing operations, and transfer means responsive to said controlling means upon the completion of said testing operations for disabling said amplifier equipment in the transmission circuit in which the fault occurs, and automatically substituting said auxiliary equipment therefor, said transfer' means cooperating with the controlling means of said transmission circuits to selectively substitute said auxiliary equipment in the one of said transmission circuits in which a fault occurs.

7. The transmission system4 in accordance with claim 6 including a protective arrangement for preventing the auxiliary equipment appropriated for any one of said transmission circuits from being subsequently appropriated by any other transmission circuit in which a fault may occur. 40

JOHN C. WALTER. 

